Method for selectively depositing a metallic film on a substrate

ABSTRACT

A method for selectively depositing a metallic film on a substrate comprising a first dielectric surface and a second metallic surface is disclosed. The method may include, exposing the substrate to a passivating agent, performing a surface treatment on the second metallic surface, and selectively depositing the metallic film on the first dielectric surface relative to the second metallic surface. Semiconductor device structures including a metallic film selectively deposited by the methods of the disclosure are also disclosed.

FIELD OF INVENTION

The present disclosure relates generally to methods for selectivelydepositing a metallic film on a substrate and particular disclosesmethods for selectively depositing a metallic film on a dielectricsurface relative to a metal surface. The disclosure is also related tosemiconductor device structures including a metallic film depositedselectively.

BACKGROUND OF THE DISCLOSURE

In some applications, it may be desirable to deposit a metallic filmonly on certain areas of a substrate. Typically, such discriminatingresults are achieved by depositing a continuous metallic film andsubsequently patterning the metallic film using lithography and etchsteps. Such lithography and etch processes may be time consuming andexpensive, and do not offer the precision required for manyapplications. A possible solution is the use of selective depositionprocesses, whereby a metallic film is deposited only in the desiredareas thereby eliminating the need for subsequent patterning steps.Selective deposition processes for semiconductor device structures maytake a number of forms, including, but not limited to, selectivedielectric deposition on dielectric surfaces (DoD), selective dielectricdeposition on metallic surfaces (DoM), selective metal deposition ondielectric surfaces (MoD) and selective metal deposition on metallicsurfaces (MoM).

Selective metal deposition on dielectric surfaces (MoD) is of interestfor providing methods for selectively depositing metal films overdielectric surfaces without the need for complex patterning and etchsteps. A common method for producing a substrate including selectivemetal over dielectric surfaces may comprise a blanket deposition of ametallic film over the entire surface of the substrate, covering boththe metal surfaces and the dielectric surfaces, and subsequent forming aphotolithography mask layer (or if required a double patterned masklayer) over the surface of the blanket metal film, the mask layer beingdisposed over the regions where the metallic film is to remain. Thesubstrate is then exposed to a metallic etch process, such as a wet etchor a dry etch, which will remove the metallic film from the exposedregions of the substrate not covered by the photolithographic mask.Subsequent processes may remove the remaining photolithographic mask,thereby forming a substrate comprising a metallic film disposed over adielectric surface. However, such processes for the formation ofmetallic films over dielectric surfaces, i.e., blanket deposition,masking and etching, are complex, time consuming, cost prohibitive andsuch processes only become more complex as device feature size decreasesat advanced technology nodes. Accordingly, methods are desired forselectively depositing a metallic film on a dielectric surface relativeto a metallic surface and particularly methods for selectivelydepositing tungsten films on dielectric surfaces.

SUMMARY OF THE DISCLOSURE

This summary is provided to introduce a selection of concepts in asimplified form. These concepts are described in further detail in thedetailed description of example embodiments of the disclosure below.This summary is not intended to identify key features or essentialfeatures of the claimed subject matter, nor is it intended to be used tolimit the scope of the claimed subject matter.

In some embodiments, methods for selectively depositing a metallic filmon a substrate comprising a first dielectric surface and a secondmetallic surface are provided. The method may comprise, exposing thesubstrate to a passivating agent, performing a surface treatment on thesecond metallic surface, and selectively depositing the metallic film onthe first dielectric surface relative to the second metallic surface.

For purposes of summarizing the invention and the advantages achievedover the prior art, certain objects and advantages of the invention havebeen described herein above. Of course, it is to be understood that notnecessarily all such objects or advantages may be achieved in accordancewith any particular embodiment of the invention. Thus, for example,those skilled in the art will recognize that the invention may beembodied or carried out in a manner that achieves or optimizes oneadvantage or group of advantages as taught or suggested herein withoutnecessarily achieving other objects or advantages as may be taught orsuggested herein.

All of these embodiments are intended to be within the scope of theinvention herein disclosed. These and other embodiments will becomereadily apparent to those skilled in the art from the following detaileddescription of certain embodiments having reference to the attachedfigures, the invention not being limited to any particular embodiment(s)disclosed.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

While the specification concludes with claims particularly pointing outand distinctly claiming what are regarded as embodiments of theinvention, the advantages of embodiments of the disclosure may be morereadily ascertained from the description of certain examples of theembodiments of the disclosure when read in conjunction with theaccompanying drawings, in which:

FIG. 1 is a process flow diagram illustrating an exemplary selectivedeposition method according to the embodiments of the disclosure;

FIG. 2 illustrates a scanning electron microscopy (SEM) cross-sectionalimage of a semiconductor structure including a selective metallic filmdeposited according to the embodiments of the disclosure;

FIGS. 3A, 3B, 3C and 3D illustrate a method of fabricating asemiconductor device structure including a selective metallic filmdeposited according to the embodiments of the disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Although certain embodiments and examples are disclosed below, it willbe understood by those in the art that the invention extends beyond thespecifically disclosed embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Thus, it is intended thatthe scope of the invention disclosed should not be limited by theparticular disclosed embodiments described below.

The illustrations presented herein are not meant to be actual views ofany particular material, structure, or device, but are merely idealizedrepresentations that are used to describe embodiments of the disclosure.

As used herein, the term “substrate” may refer to any underlyingmaterial or materials that may be used, or upon which, a device, acircuit or a film may be formed.

As used herein, the term “passivating agent” may refer to any chemicalspecies which when applied to a surface of a material, alters at leastthe surface of that material in a manner which will reduce its chemicalreactivity.

As used herein, the term “passivating layer” may refer to any layer, orpartial layer, of material disposed over a surface which alters thesurface in a manner which will reduce its chemical reactivity.

As used herein, the term “metallic surface” may refer to surfacesincluding a metallic component, including, but not limited to, metalsurfaces, metal oxide surfaces, metal silicide surfaces, metal nitridesurfaces and metal carbide surfaces.

As used herein, the term “atomic layer deposition” (ALD) may refer to avapor deposition process in which deposition cycles, preferably aplurality of consecutive deposition cycles, are conducted in a processchamber. Typically, during each cycle the precursor is chemisorbed to adeposition surface (e.g., a substrate surface or a previously depositedunderlying surface such as material from a previous ALD cycle), forminga monolayer or sub-monolayer that does not readily react with additionalprecursor (i.e., a self-limiting reaction). Thereafter, if necessary, areactant (e.g., another precursor or reaction gas) may subsequently beintroduced into the process chamber for use in converting thechemisorbed precursor to the desired material on the deposition surface.Typically, this reactant is capable of further reaction with theprecursor. Further, purging steps may also be utilized during each cycleto remove excess precursor from the process chamber and/or remove excessreactant and/or reaction byproducts from the process chamber afterconversion of the chemisorbed precursor. Further, the term “atomic layerdeposition,” as used herein, is also meant to include processesdesignated by related terms such as, “chemical vapor atomic layerdeposition”, “atomic layer epitaxy” (ALE), molecular beam epitaxy (MBE),gas source MBE, or organometallic MBE, and chemical beam epitaxy whenperformed with alternating pulses of precursor composition(s), reactivegas, and purge (e.g., inert carrier) gas.

As used herein, the term “film” and “thin film” may refer to anycontinuous or non-continuous structures and material deposited by themethods disclosed herein. For example, “film” and “thin film” couldinclude 2D materials, nanorods, nanotubes, or nanoparticles or evenpartial or full molecular layers or partial or full atomic layers orclusters of atoms and/or molecules. “Film” and “thin film” may comprisematerial or a layer with pinholes, but still be at least partiallycontinuous.

The embodiments of the disclosure may include methods for selectivelydepositing a metallic film on a substrate and particularly methods forselectively depositing a metallic film on a dielectric surface relativeto a metallic surface, i.e., a metal on dielectric selective depositionprocess. As a non-limiting example of the embodiments of the disclosure,a tungsten film may be selectively deposited on a dielectric surfacerelative to a metallic surface.

The selective deposition processes described herein may be utilized todeposit a metallic film selectively on a dielectric surface without theneed for additional photolithography and/or etch steps. The selectivedeposition processes described herein therefore simplify devicefabrication processes by reducing the number of photolithographic maskstages and/or etch stages. In addition, the ability to selectivelydeposit a metallic film on a dielectric surface may enable improveddevice performance by eliminating the deposition of certain undesirablemetallic films on metallic surfaces.

A possible application for selective metal on dielectric depositionprocesses includes the selective deposition of tungsten (W) ondielectric surfaces relative to metallic surfaces. For example, a commonsemiconductor device structure may comprise a metal contact structureconsisting of a contact hole etched into a dielectric film, such as asilicon oxide, to reveal the underlying metal. A barrier metal, such as,for example, a titanium nitride (TiN) film may be deposited on both theside walls of the contact hole as well as on the underlying metal and ahighly resistive tungsten (W) nucleation layer be deposited on thetitanium nitride film. Finally, a contact plug of low resistivitytungsten (W) is utilized to complete the contact structure. However, insuch a contact structure the electrical resistivity of the contact isstrongly increased by the presence of the titanium nitride barrier metaland the highly resistive tungsten nucleation layer on the surface of theunderlying metal contact. Utilizing a selective metal on dielectricprocess for tungsten deposition, the titanium nitride barrier layer maybe eliminated and tungsten may be deposited directly on the sidewalls ofthe dielectric hole. In such a process, no titanium nitride or highlyresistivity tungsten is deposited on the underlying metal and a lowresistivity tungsten may be immediately deposited in the contact hole,thereby reducing the electrical contact resistance.

A selective deposition process may involve depositing a greater amountof material on a first surface relative to a second surface. Forexample, for a metal on dielectric selective deposition process, theselective deposition process may deposit a greater amount of a metallicfilm on a first dielectric surface relative to a second metallicsurface. In some embodiments of the disclosure, the selectivity of thedeposition process may be expressed as the ratio of material formed onthe first surface relative to the amount of material formed on the firstand second surfaces combined. For example, if a selective depositionprocess deposits 10 nm of tungsten on a first dielectric surface and 1nm of tungsten on a second metallic surface, the selective depositionprocess will be considered to have 90% selectivity. In some embodiments,the selectivity of the methods disclosed herein may be above about 80%,above about 90%, above about 95%, or even about 100%. In someembodiments, the selectivity of the deposition process is at least about80%, which may be selective enough for some particular applications. Insome cases the selectivity is at least about 50%, which may be selectiveenough for some particular applications.

A non-limiting example embodiment of the methods of the disclosure isillustrated in FIG. 1, which illustrates method 100 for selectivelydepositing a metallic film on a first dielectric surface relative to asecond metallic surface. The method 100 may proceed with process block110 which may comprise providing a substrate into a first reactionchamber and heating the substrate to a process temperature.

In more detail, in some embodiments of the disclosure the, substrate maycomprise a planar substrate or a patterned substrate. Patternedsubstrates may comprise substrates that may include semiconductor devicestructures formed into or onto a surface of the substrate, for example,the patterned substrates may comprise partially fabricated semiconductordevice structures such as transistors and memory elements. The substratemay comprise a first dielectric surface and a second metallic surface,in other words the surface of the substrate may comprise a plurality offirst dielectric surfaces and a plurality of second metallic surfaces.

In some embodiments of the disclosure, the first dielectric surface maycomprise a low dielectric constant material, i.e., a low-k material,which may be defined as an insulator with a dielectric constant lessthan about 4.0. In some embodiments the dielectric constant of the low-kmaterial may less than about 3.5, or less than about 3.0, or less thanabout 2.5, or even less than about 2.3. In some embodiments, the firstdielectric surface may comprise a first silicon containing surface. Forexample, the first dielectric surface may comprise at least one of asilicon oxide, a silicon nitride, a silicon carbide, a siliconoxynitride, or mixtures thereof. In some embodiments of the disclosure,the first dielectric surface may comprise a porous material thatcontains pores which are connected to each other.

In some embodiments, the second metallic surface may comprise anelemental metal, such as, for example, copper (Cu), cobalt (Co), nickel(Ni), or tungsten (W). In some embodiments, the second metallic surfacemay comprise at least one of a pure metal, a metallic oxide, a metallicnitride, a metallic silicide, a metallic carbide, or mixtures thereof.In some embodiments, the second metallic surface may comprise a nativeoxide of metal containing material. In some embodiments, the secondmetallic surface may comprise a transition metal. For example, thetransition metal may comprise one or more of Ti, V, Cr, Mn, Nb, Mo, Ru,Rh, Pd, Ag, Au, Hf, Ta, W, Re, Os, Ir, or Pt.

The method 100 may continue with process block 110 by loading thesubstrate into a suitable first reaction chamber. The first reactionchamber may be configured for performing all, or a portion, of theremaining process blocks of selective deposition method 100. In someembodiments of the disclosure, the first reaction chamber may beconfigured to optionally outgas the substrate (i.e., process block 120)and expose the substrate to a passivating agent (i.e., process block130). However, in additional embodiments of the disclosure, the firstreaction chamber maybe configured to perform all of the process blockscomprising selective deposition method 100.

Reactors, and their associated reaction chambers, capable of selectivedeposition of a metallic film on a dielectric surface can be used toperform the selective deposition method 100. Such reactors include ALDreactors, as well as CVD reactors equipped with appropriate equipmentand means for providing precursors. According to some embodiments ashowerhead reactor may be used. According to some embodiments a plasmareactor, such as plasma enhanced ALD reactor, may be used. Plasma may bedirect or remote or in near vicinity of the substrate. According to someembodiments a thermal reactor i.e., non-plasma reactor, such as thermalALD reactor may be used.

Examples of suitable reactors and associated reaction chambers that maybe used include commercially available single substrate (or singlewafer) deposition equipment such as Pulsar® reactors (such as thePulsar® 2000 and the Pulsar® 3000 and Pulsar® XP ALD), and EmerALD® XPand the EmerALD® reactors, available from ASM America, Inc. of Phoenix,Ariz. and ASM Europe B.V., Almere, Netherlands. Other commerciallyavailable reactors include those from ASM Japan K.K. (Tokyo, Japan)under the tradename Eagle® XP and XP8. In some embodiments the reactoris a spatial ALD reactor, in which the substrates moves or rotatesduring processing.

In some embodiments a batch reactor may be used. Suitable batch reactorsinclude, but are not limited to, Advance® 400 Series reactorscommercially available from and ASM Europe B.V. (Almere, Netherlands)under the trade names A400 and A412 PLUS. In some embodiments, avertical batch reactor is utilized in which the boat rotates duringprocessing, such as the A412. Thus, in some embodiments, the wafersrotate during processing. In other embodiments, the batch reactorcomprises a mini-batch reactor configured to accommodate 10 or fewerwafers, 8 or fewer wafers, 6 or fewer wafers, 4 or fewer wafers, or 2wafers. In some embodiments in which a batch reactor is used,wafer-to-wafer uniformity is less than 3% (1 sigma), less than 2%, lessthan 1% or even less than 0.5%.

The deposition processes described herein can optionally be carried outin a reactor or reaction space connected to a cluster tool. In a clustertool, because each reaction space is dedicated to one type of process,the temperature of the reaction space in each module can be keptconstant, which improves the throughput compared to a reactor in whichthe substrate is heated up to the process temperature before each run.Additionally, in a cluster tool it is possible to reduce the time topump the reaction space to the desired process pressure levels betweensubstrates.

In some embodiments of the disclosure, a stand-alone reactor can beequipped with a load-lock. In that case, it is not necessary to cooldown the reaction space between each run.

Once the substrate has been loaded into the first reaction chamber, thesubstrate may be heated to a suitable process temperature. In someembodiments of the disclosure, process block 110 of selective depositionmethod 100 may comprise heating the substrate to a temperature greaterthan 250° C., or greater than 300° C., or greater than 350° C., or evengreater than 400° C. In some embodiments of the disclosure the substratemay be heated to a temperature of approximately 250° C.

The selective deposition method 100 may continue with optional processblock 120, wherein the substrate goes through an outgassing process. Insome embodiments of the disclosure, the outgassing of the substrate maycomprise heating the substrate to a temperature greater than 250° C. fora time period of greater than approximately 1 minute, or greater thanapproximately 5 minutes, or even greater than approximately 10 minutes.The outgassing of the substrate may be performed to remove unwantedspecies from the surface of the substrate, for example, the outgassingprocess may be performed to remove moisture from the substrate.

Once the substrate has undergone the optional outgassing process theselective deposition method 100 may continue with process block 130,wherein the substrate is exposed to a passivating agent. In someembodiments of the disclosure, exposing the substrate to a passivatingagent may comprise exposing the substrate to an alkylhalosilane, whereinthe alkylhalosilane may have the general formula X_(y)—Si—R_(4-y),wherein R is a hydrocarbon, such as, for example, an alkyl (e.g., aC1-C3 alkyl), X is a halide, such as, for example, chlorine (Cl) orfluorine (F), and y is an integer from 1 to 3, from 1 to 2, or 1. Insome embodiments, exposing the substrate to a passivating agent maycomprise exposing the substrate to a chemical agent having the generalformula (NR^(II) ₂)_(y)—Si—R^(I) _(4-y), wherein R^(II) is a C1-C5alkyl, R^(I) is a hydrocarbon, such as, for example, a C1-C3 alkyl, andy is an integer from 1 to 3, from 1 to 2, or 1. In some embodiments ofthe disclosure, exposing the substrate to a passivating agent maycomprise exposing the substrate to trimethyl(dimethylamino)silane. Insome embodiments, exposing the substrate to a passivating agent maycomprise flowing the passivating agent into the first reaction chamberat a flow rate of approximately greater than 1 sccm, or approximatelygreater than 5 sccm, or approximately greater than 25 sccm, orapproximately greater than 50 sccm, or approximately greater than 100sccm, or even approximately greater than 500 sccm.

The process of exposing the substrate to a passivating agent may beperformed at a substrate temperature of greater than approximately 250°C., or greater than 300° C., or great than 350° C., or even greater than400° C. In some embodiments of the disclosure, the process of exposingthe substrate to a passivating agent may be performed at a temperatureof approximately 250° C. In some embodiments of the disclosure, exposingthe substrate to a passivating agent may be performed for a time periodof greater than 1 second, or greater than 30 seconds, or greater than 1minute, or greater than 2 minutes, or even greater than 5 minutes. Insome embodiments, exposing the substrate to a passivating agent may beperformed for a time period of approximately 15 seconds. In someembodiments of the disclosure, the pressure within the first reactionchamber when exposing the substrate to the passivating agent may be lessthan 10 Torr, or less than 5 Torr, or even less than 2 Torr. In someembodiments of the disclosure, the pressure within the first reactionchamber when exposing the substrate to the passivating agent may bebetween 1 Torr and 760 Torr.

Once the substrate has been exposed to the passivating agent anyremaining passivating agent may be removed from the first reactionchamber, for example, a vacuum may utilized to remove any remainingpassivating agent from the first reaction chamber and/or a purge gas(e.g., nitrogen or argon) may be used to “flush” the first reactionchamber.

The selective deposition method 100 may continue with process block 140,which comprises performing a surface treatment on the second metallicsurface of the substrate. For example, when the second metallic surfacecomprises a substantially elemental metal surface, then the surfacetreatment of the second metallic surface may be utilized to clean and/orreduce the second metallic surface such that a pure elemental metal ison the substrate surface. As a non-limiting example embodiment, thesecond metallic surface may comprise a copper surface and the surfacetreatment may be utilized to clean and/or reduce the copper surface to apure elemental copper surface.

In some embodiments of the disclosure, the second metallic surface maybe covered, or at least partially covered, with a passivating layer,wherein the passivating layer may reduce the reactivity of theunderlying second metallic surface. For example, the second metallicsurface may comprise copper and the copper may be substantially coveredwith a passivating layer comprising benzotriazole (BTA) or abenzotriazole derivative. For example, benzotriazole derivatives mayinclude substituted benzotriazoles having a benzene ring substitutedwith hydroxy; alkoxy such as methoxy and ethoxy; amino; nitro; alkylsuch as methyl, ethyl and butyl; halogen such as fluorine, chlorine,bromine and iodine. Therefore, in some embodiments of the disclosure,the second metallic surface may be at least partially covered with apassivating layer comprising benzotriazole and a surface treatment maybe performed to remove the benzotriazole from the surface of the secondmetallic surface, for example, from the surface of a copper metal.

In some embodiments of the disclosure, removing the passivating layerfrom the second metallic surface may comprise exposing the passivatinglayer to a reactant, such as, for example, at least one of formic acid(HCOOH), acetic acid (CH₃COOH), or propanoic acid (CH₃CH₂COOH). In someembodiments, the reactant may include an alcohol. In some embodiments,the reactant may include an aldehyde. In some embodiments, the reactantmay have at least one functional group selected from the groupconsisting of alcohol (—OH), aldehyde (—CHO), and carboxylic acid(—COOH).

Without being limited by any particular theory or mode of operation, theprocess for eroding and/or removing the passivating layer can includereducing one or more components of the passivating layer by using thereactant, such that at least a portion of the passivating layer may beremoved from the substrate surface. In some embodiments, the passivatinglayer may be eroded and/or removed utilizing a reactant, including acarboxylic acid. Reaction between the passivating layer and thecarboxylic acid may generate one or more volatile byproducts which maybe readily transported away from the substrate surface and removed fromthe reaction space. For example, the carboxylic acid may reduce anoxidized copper forming part of the passivating layer such that theoxidized copper may be restored to its elemental state.

In some embodiments of the disclosure, eroding and/or removing thepassivating layer may not comprise reducing one or more components ofthe passivating layer. For example, the reactant may interact with oneor more components of the passivating layer to erode and/or remove thepassivating layer without or substantially without reducing anycomponents of the passivating layer.

Reactants containing at least one alcohol group may be selected from thegroup consisting of primary alcohols, secondary alcohols, tertiaryalcohols, polyhydroxy alcohols, cyclic alcohols, aromatic alcohols, andother derivatives of alcohols.

In some embodiments, the primary alcohols may have an —OH group attachedto a carbon atom which is bonded to another carbon atom, in particularprimary alcohols according to the general formula (I):

R¹—OH  (I)

wherein R¹ is a linear or branched C₁-C₂₀ alkyl or alkenyl group, suchas, for example, methyl, ethyl, propyl, butyl, pentyl, or hexyl. Innon-limiting example embodiments of the disclosure, the primary alcoholsmay comprise methanol, ethanol, propanol, butanol, 2-methyl propanol, or2-methyl butanol.

In some embodiments, the secondary alcohols may have an —OH groupattached to a carbon atom that is bonded to two other carbon atoms. Inparticular, secondary alcohols may have the general formula (II):

wherein each R¹ is selected independently from the group of linear orbranched C₁-C₂₀ alkyl and alkenyl groups, such as, for example, methyl,ethyl, propyl, butyl, pentyl, or hexyl. As a non-limiting exampleembodiment of the disclosure, the second alcohols may comprise2-propanol, or 2-butanol.

In some embodiments, the tertiary alcohols may have an —OH groupattached to a carbon atom that is bonded to three other carbon atoms. Inparticular, tertiary alcohols may have the general formula (III):

wherein each R¹ is selected independently from the group of linear orbranched C₁-C₂₀ alkyl and alkenyl groups, such as, for example, methyl,ethyl, propyl, butyl, pentyl, or hexyl. As a non-limiting exampleembodiment of the disclosure, the tertiary alcohols may comprisetert-butanol.

In some embodiments, polyhydroxy alcohols, such as diols and triols,have primary, secondary and/or tertiary alcohol groups as describedabove. Examples of polyhydroxy alcohols include, but are not limited to,ethylene glycol and glycerol.

In some embodiments, cyclic alcohols have an —OH group attached to atleast one carbon atom which is part of a ring of 1 to 10, or between 5-6carbon atoms.

In some embodiments, aromatic alcohols have at least one —OH groupattached to either a benzene ring or to a carbon atom in a side chain.

In some embodiments, reactants containing at least one aldehyde group(—CHO) are selected from the group consisting of compounds having thegeneral formula (V), alkanedial compounds having the general formula(VI), and other derivatives of aldehydes.

Therefore, in some embodiments, the reactant may comprise an aldehydehaving the general formula (V):

R³—CHO  (V)

wherein R³ is selected from the group consisting of hydrogen and linearor branched C₁-C₂₀ alkyl and alkenyl groups, such as, for example,methyl, ethyl, propyl, butyl, pentyl, or hexyl. In some embodiments, R³is selected from the group consisting of methyl or ethyl. Examples ofcompounds according to formula (V) are formaldehyde, acetaldehyde andbutyraldehyde.

In some embodiments, reactant are aldehydes having the general formula(VI):

OHC—R⁴—CHO  (VI)

wherein R⁴ is a linear or branched C₁-C₂₀ saturated or unsaturatedhydrocarbon. Alternatively, the aldehyde groups may be directly bondedto each other (R⁴ is null).

In some embodiments, reactants containing at least one —COOH group areselected from the group consisting of compounds of the general formula(VII), polycarboxylic acids, and other derivatives of carboxylic acids.

Therefore, in some embodiments, reactants are carboxylic acids havingthe general formula (VII);

R⁵—COOH  (VII)

wherein R⁵ is hydrogen or linear or branched C₁-C₂₀ alkyl or alkenylgroup, such as, for example, methyl, ethyl, propyl, butyl, pentyl, orhexyl. In some embodiments, R⁵ may be a linear or branched C₁-C₃ alkylor alkenyl group. Non-limiting example embodiments of compoundsaccording to formula (VII) may comprise formic acid, propanoic acid, oracetic acid.

In some embodiments, the reactant demonstrates desired vapor pressuresuch that the reactant can be volatized without heating the reactant. Insome embodiments, such a reactant comprises only one carboxyl group(—COOH). In some embodiments, such a reactant may comprise dicarboxylicacid. In some embodiments, such a reactant is not a citric acid.

In some embodiments, the reactant may be heated to volatize the reactantprior to delivering the volatized reactant to the substrate surface. Insome embodiments, such a reactant comprises a dicarboxylic acid,including an oxalic acid.

In some embodiments, removing the passivating layer from the secondmetallic surface may comprise exposing the passivating to formic acidfor a time period of greater than 1 second, or greater than 25 seconds,or greater than 30 seconds, or greater than 1 minute, or greater than 2minutes, or even greater than 5 minutes. In some embodiments of thedisclosure, removing the passivating layer from the second metallicsurface may comprise heating the substrate to a temperature greater than20° C., or greater than 100° C., or greater than 150° C., or greaterthan 250° C., or greater than 300° C., or greater than 350° C., or evengreater than 400° C. In some embodiments, removing the passivating layerfrom the second metallic surface may comprise heating the substrate to atemperature of approximately 250° C.

In some embodiments of the disclosure, performing a surface treatment ofthe second metallic surface may reduce the second metallic surface. Insome embodiments the surface treatment may remove any native oxide thatmay be present on the second metallic surface. In some embodiments, thesurface treatment may remove any hydrocarbon layer that may be presenton the second metallic surface. In some embodiments, the surfacetreatment may provide active sites on the second metallic surface.

The surface treatment of the second metallic surface may be done in anyof a variety of methods, for example, using a chemical such as formicacid or using a plasma. For example, the substrate surface may becleaned using a hydrogen containing plasma or radicals, such as H-plasmaor NH₃ plasma. In some embodiments, hydrochloric acid (HCl) treatmentmay be used as the surface treatment method. In some embodiments, thesecond metallic surface treatment process may comprise exposing thesubstrate to a treatment reactant, such as, for example, formic acid.Other second metallic surface treatment methods are also possible; thespecific surface treatment methods to be used in any particular case canbe selected based on a variety of factors, such as, the materials andthe deposition conditions, including, for example, the types ofmaterials on the substrate surface.

The selective deposition method 100 may continue with process block 150,wherein the substrate is transferred to a second reaction chamber andthe substrate is heated to a desired process temperature. In someembodiments of the disclosure, the first reaction and the secondreaction chamber may comprise the same reaction chamber and in suchembodiments the substrate may not undergo a transfer process, i.e., theselective deposition method 100 is performed in a single reactionchamber. In alternative embodiments, the first reaction chamber and thesecond reaction chamber may comprise different reaction chambers and thesubstrate may be transferred from the first reaction chamber to thesecond reaction chamber. In some embodiments, the first reaction chamberand the second reaction chamber may comprise a cluster tool wherein thetransfer of the substrate from the first reaction chamber to the secondreaction chamber may be performed under a controlled environment withoutexposure to the ambient atmosphere. In some embodiments, the secondreaction chamber may comprise a reaction chamber configured for adeposition process, such as, for example, an atomic layer depositionchamber or a chemical vapor deposition chamber.

Once the substrate is transferred to the second reaction chamber, thesubstrate may be heated to a desired process temperature. In someembodiments of the disclosure, the substrate may be heated to a desireddeposition temperature in the second reaction chamber. In someembodiments, the substrate may be heated to a deposition temperature ofgreater than approximately 50° C., or greater than approximately 100°C., or greater than approximately 150° C., or greater than approximately200° C., or greater than approximately 250° C., or greater thanapproximately 300° C., or greater than approximately 350° C., or evengreater than approximately 400° C. In some embodiments of thedisclosure, the substrate may be heated to a temperature ofapproximately 50° C.

The selective deposition method 100 may proceed with process block 160which comprises selectively depositing a metallic film on the firstdielectric surface relative to the second metallic surface. In someembodiments of the disclosure, the selective deposition process maycomprise a cyclical deposition process, such as, for example, one ofatomic layer deposition or cyclical chemical vapor deposition.

A non-limiting example embodiment of a cyclical deposition process mayinclude ALD, wherein ALD is based on typically self-limiting reactions,whereby sequential and alternating pulses of reactants are used todeposit about one atomic (or molecular) monolayer of material perdeposition cycle. The deposition conditions and precursors are typicallyselected to provide self-saturating reactions, such that an absorbedlayer of one reactant leaves a surface termination that is non-reactivewith the vapor phase reactants of the same reactant. The substrate issubsequently contacted with a different reactant that reacts with theprevious termination to enable continued deposition. Thus, each cycle ofalternating pulsed reactants typically leaves no more than about onemonolayer of the desired material. However, as mentioned above, theskilled artisan will recognize that in one or more ALD cycles more thanone monolayer of material may be deposited, for example, if some gasphase reactions occur despite the alternating nature of the process.

In an ALD-type process for depositing a metallic film, one depositioncycle may comprise exposing the substrate to a first reactant, removingany unreacted first reactant and reaction byproducts from the reactionspace and exposing the substrate to a second reactant, followed by asecond removal step. The first reactant may comprise a metal containingprecursor, such as a tungsten containing precursor, and the secondreactant may comprise a reducing agent precursor.

Precursors may be separated by inert gases, such as argon (Ar) ornitrogen (N₂), to prevent gas phase reactions between reactants andenable self-saturating surface reactions. In some embodiments, however,the substrate may be moved to separately contact a first vapor phasereactant and a second vapor phase reactant. Because the reactionsself-saturate, strict temperature control of the substrates and precisedosage control of the precursor may not be required. However, thesubstrate temperature is preferably such that an incident gas speciesdoes not condense into monolayers nor decompose on the substratesurface. Surplus chemicals and reaction byproducts, if any, are removedfrom the substrate surface, such as by purging the reaction space or bymoving the substrate, before the substrate is contacted with the nextreactive chemical. Undesired gaseous molecules can be effectivelyexpelled from the reaction space with the help of an inert purging gas.A vacuum pump may be used to assist in the purging process.

In some embodiments, cyclical deposition processes are used toselectively deposit metallic films on a substrate and the cyclicaldeposition process may be an ALD type process. In some embodiments, thecyclical deposition may be a hybrid ALD/CVD or cyclical CVD process. Forexample, in some embodiments the deposition or growth rate of the ALDprocess may be low compared with a CVD process. One approach to increasethe growth rate may be that of operating at a higher substratetemperature than that typically employed in an ALD process, resulting ina chemical vapor deposition process, but still taking advantage of thesequential introduction or precursor, such a process may be referred toas cyclical CVD.

According to some embodiments of the disclosure, ALD processes are usedto selectively deposit a metallic film on a dielectric surface of asubstrate, such as an integrated circuit workpiece. In some embodiments,each ALD cycle may comprise two distinct deposition steps or phases. Ina first phase of the deposition cycle (“the metal phase”), the substratesurface on which deposition is desired is contacted with a first vaporphase reactant comprising at least one metal containing vapor phasereactant which chemisorbs onto the substrate surface, forming no morethan about one monolayer of reactant species on the surface of thesubstrate. In a second phase of the deposition cycle (“the reducingphase”), the substrate surface on which deposition is desired iscontacted with a second vapor phase reactant comprising at least onereducing agent precursor which reacts with the previously chemisorbedspecies to selectively form a metallic film on a dielectric surface of asubstrate.

In some embodiments, the metal containing precursor, also referred tohere as the “metal compound” may comprise a metal. In some embodiments,the metal may comprise a transition metal. In some embodiments of thedisclosure, the metal may be selected from the group of: Ti, Co, V, Cr,Mn, Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir and Pt. In someembodiments the metal containing precursor may comprise at least one ofCo, Ru, W, Ta, Nb, Ti, Mo, or V. In some embodiments the metalcontaining precursor comprises tungsten (W).

In some embodiments of the disclosure, the metal containing precursormay comprise a metal halide (F, Cl, Br, I). In some embodiments themetal containing precursor may comprise a transition metal halide. Forexample, as a non-limiting example embodiment, the metal containingprecursor may comprise at least one of WF₆, TaF₅, NbF₅, TiF₄, MoF_(x) orVF_(x). In some embodiments of the disclosure, the metal containingprecursor may comprise tungsten hexafluoride (WF₆).

In some embodiments, exposing the substrate to the at least one metalcontaining vapor phase reactant may comprise pulsing the metal precursorover the substrate for a time period between about 0.01 second and about60 seconds, between about 0.05 seconds and about 10 seconds, or betweenabout 0.1 seconds and about 5.0 seconds. In addition, during the pulsingof the metal precursor over the substrate the flow rate of the metalprecursor may be less than 1000 sccm, or less than 500 sccm, or lessthan 250 sccm, or less than 100 sccm, or even less than 50 sccm.

Excess metal precursor and reaction byproducts (if any) may be removedfrom the substrate surface, e.g., by pumping with an inert gas. Forexample, in some embodiments of the disclosure the methods may include apurge cycle wherein the substrate surface is purged for a time period ofless than approximately 2.0 seconds. Excess metal precursor and anyreaction byproducts may be removed with the aid of a vacuum generated bya pumping system.

In a second phase of the deposition cycle (“the reducing phase”) thesubstrate is contacted with a second vapor phase reactant comprising atleast one reducing agent precursor. In some embodiments of thedisclosure, the at least one reducing agent containing vapor reactantmay comprise at least of one of hydrogen (H₂), silane (SiH₄), disilane(Si₂H₆), trisilane (Si₃H₈), germane (GeH₄), digermane (Ge₂H₆), ordiborane (B₂H₆). In some embodiments, the at least one reducing agentmay comprise a plasma, such as, for example, a hydrogen plasmacomprising atomic hydrogen, hydrogen ions and hydrogen radicals. In someembodiments the reducing agent precursor may comprise higher ordersilanes with the general empirical formula Si_(x)H_((2x+x)). In someembodiments the reducing agent precursor may comprise higher ordergermanes with the general empirical formula Ge_(x)H_((2x+2)).

In some embodiments, exposing the substrate to the reducing agent vaporphase reactant may comprise pulsing the reducing agent precursor (e.g.,disilane) over the substrate for a time period of between about 0.01seconds and about 60 seconds, between about 0.05 seconds and about 10seconds, or between about 0.1 seconds and about 5.0 seconds. During thepulsing of the reducing agent precursor over the substrate the flow rateof the reducing agent precursor may be less than 1000 sccm, or less than500 sccm, or less than 250 sccm, or less than 100 sccm, or even lessthan 50 sccm.

The second vapor phase reactant comprising a reducing agent reactant mayreact with metal-containing molecules left on the substrate. In someembodiments, the reducing agent precursor is capable of reducing themetal-containing molecules left on the substrate to form a selectiveelemental metal on the dielectric surfaces of the substrate. In someembodiments of the disclosure the selective elemental metal may comprisetungsten (W).

Excess second source chemical and reaction byproducts, if any, may beremoved from the substrate surface, for example, by a purging gas pulseand/or vacuum generated by a pumping system. Purging gas is preferablyany inert gas, such as, without limitation, argon (Ar), nitrogen (N₂),or helium (He). A phase is generally considered to immediately followanother phase if a purge (i.e., purging gas pulse) or other reactantremoval step intervenes.

The deposition cycle in which the substrate is alternatively contactedwith the first vapor phase reactant (i.e., the metal containingprecursor) and the second vapor phase reactant (i.e., the reducing agentprecursor) may be repeated two or more times until a desired thicknessof a selective metallic film is deposited. It should be appreciated thatin some embodiments of the disclosure, the order of the contacting ofthe substrate with the first phase reactant and the second vapor phasereactant may be such that the substrate is first contacted with thesecond vapor phase reactant followed by the first vapor phase reactant.In addition, in some embodiments, the cyclical deposition process maycomprise contacting the substrate with the first vapor phase reactant(i.e., the metal containing precursor) one or more times prior tocontacting the substrate with the second vapor phase reactant (i.e., thereducing agent precursor) one or more times and similarly mayalternatively comprise contacting the substrate with the second vaporphase reactant one or more times prior to contacting the substrate withthe first vapor phase reactant one or more times. In addition, someembodiments of the disclosure may comprise non-plasma reactants, e.g.,the first and second vapor phase reactants are substantially free ofionized reactive species. In some embodiments, the first and secondvapor phase reactants are substantially free of ionized reactivespecies, excited species or radical species. For example, both the firstvapor phase reactant and the second vapor phase reactant may comprisenon-plasma reactants to prevent ionization damage to the underlyingsubstrate and the associated defects thereby created.

The cyclical deposition processes described herein, utilizing a metalcontaining precursor and a reducing agent precursor to form a selectivemetallic film on dielectric surfaces of the substrate, may be performedin an ALD or CVD deposition system with a heated substrate. For example,in some embodiments, methods may comprise heating the substrate totemperature of between approximately 50° C. and approximately 150° C.,or even heating the substrate to a temperature of between approximately50° C. and approximately 120° C. Of course, the appropriate temperaturewindow for any given cyclical deposition process, such as, for an ALDreaction, will depend upon the surface termination and reactant speciesinvolved. Here, the temperature varies depending on the precursors beingused and is generally at or below about 700° C. In some embodiments, thedeposition temperature is generally at or above about 50° C. for vapordeposition processes, in some embodiments the deposition temperature isbetween about 50° C. and about 250° C., and in some embodiments thedeposition temperature is between about 50° C. and about 200° C. In someembodiments the deposition temperature is below about 500° C., belowabout 400° C. or below about 300° C. In some instances the depositiontemperature can be below about 200° C., below about 150° C. or belowabout 100° C., for example, if additional reactants or reducing agentsare used in the process. In some instances the deposition temperaturecan be above about 20° C., above about 50° C. and above about 75° C. Insome embodiments of the disclosure, the deposition temperature i.e., thetemperature of the substrate during deposition is approximately 50° C.

In some embodiments the growth rate of the selective metallic film on adielectric surface may be from about 0.005 Å/cycle to about 20 Å/cycle,from about 0.05 Å/cycle to about 10 Å/cycle from about 0.1 Å/cycle toabout 10 Å/cycle, from about 1 Å/cycle to about 5 Å/cycle. In someembodiments the growth rate of the film is more than about 0.01 Å/cycle,more than about 0.05 Å/cycle, more than about 0.1 Å/cycle, more thanabout 0.5 Å/cycle, more than about 1 Å/cycle, more than about 1.5Å/cycle. In some embodiments the growth rate of the film is less thanabout 20 Å/cycle, less than about 10 Å/cycle, less than about 5 Å/cycle,In some embodiments of the disclosure, the growth rate of the W metallicfilm is approximately 1.5 Å/cycle.

In additional embodiments, the selective metallic films depositedaccording to the embodiments of the disclosure may comprise less thanabout 20 atomic % oxygen, less than about 10 atomic % oxygen, less thanabout 5 atomic % oxygen, or even less than about 2 atomic % oxygen. Infurther embodiments, the selective metallic films may comprise less thanabout 10 atomic % hydrogen, or less than about 5 atomic % of hydrogen,or less than about 2 atomic % of hydrogen, or even less than about 1atomic % of hydrogen. In yet further embodiments, the selective metallicfilms may comprise less than about 10 atomic % carbon, or less thanabout 5 atomic % carbon, or less than about 2 atomic % carbon, or lessthan about 1 atomic % of carbon, or even less than about 0.5 atomic %carbon. In the embodiments outlined herein, the atomic concentration ofan element may be determined utilizing Rutherford backscattering (RBS).

In some embodiments of the disclosure, the selectively depositedmetallic films may be deposited on a three-dimensional structure. Insome embodiments, the step coverage of the metallic thin film may beequal to or greater than about 50%, or greater than about 80%, orgreater than about 90%, or greater than about 95%, or greater than about98%, or greater than about 99% or greater in structures having aspectratios (height/width) of more than about 2, more than about 5, more thanabout 10, more than about 25, more than about 50, or even more thanabout 100.

In some embodiments, the selective metallic film deposited according tosome of the embodiments described herein may have a thickness greaterthan about 20 nm, greater than about 30 nm, greater than about 40 nm,greater than about 50 nm, greater than about 60 nm, greater than about100 nm, greater than about 250 nm, greater than about 500 nm, orgreater. In some embodiments a selective metallic film depositedaccording to some of the embodiments described herein may have athickness of less than about 50 nm, less than about 30 nm, less thanabout 20 nm, less than about 15 nm, less than about 10 nm, less thanabout 5 nm, less than about 3 nm, less than about 2 nm, or even lessthan about 1 nm.

In some embodiments of the disclosure, the selective deposition processmay deposit a greater amount of a metallic film on a first dielectricsurface relative to a second metallic surface. In some embodiments, theselectivity of the methods disclosed herein may be greater thanapproximately 80%, greater than approximately 90%, greater thanapproximately 95%, or even approximately 100%. In some embodiments, theselectivity of the deposition process is at least about 80%, which maybe selective enough for some particular applications. In some cases theselectivity is at least about 50%, which may be selective enough forsome particular applications.

As a non-limiting example embodiment of the selective deposition methodsof the current disclosure, FIG. 2 illustrates a scanning electronmicroscopy (SEM) cross-sectional image of a semiconductor structure 200including a selective metallic film deposited according to theembodiments of the disclosure. In more detail, FIG. 2 illustrates asemiconductor structure 200 which comprise a substrate 202, a patterneddielectric layer 204 and a metallic layer disposed in the patterneddielectric layer 206. In this non-limiting example structure thesubstrate 202 is a silicon substrate, the patterned dielectric layer 204is a low-k dielectric material having a dielectric constant of 2.55, andthe metallic layer disposed in the patterned dielectric layer 206 iscopper. The semiconductor structure 200 also includes the selectivemetallic film 208, which comprises tungsten (W), which is disposed onlyon the surface of the low-k dielectric material and not on the surfaceof copper metal 206 disposed within the patterned dielectric film 204.

The selective metallic films deposited by the deposition processesdisclosed herein may be utilized in a variety of contexts, such as inthe formation of semiconductor device structures. One of skill in theart will recognize that the processes described herein are applicable tomany contexts, including, but not limited to, device contact structures.

As a non-limiting example, FIGS. 3A-3D illustrate a method offabricating a semiconductor device structure including a selectivemetallic film deposited according to the embodiments of the disclosure.It should be noted that the illustrations given in FIGS. 3A-3D onlyillustrate a select portion of a semiconductor device structure, i.e.,the contact structure, and do not include the all the features of acompletely fabricated device structure, such as, for example, thesupporting substrate (e.g., a silicon substrate) and the active devicestructures (e.g., transistor structures).

In more detail, FIG. 3A illustrates a portion of semiconductor devicestructure 300 which comprises a metal contact 302, which in someembodiments may comprise a copper metal. Disposed over the metal contact302 is an interlayer dielectric 304, which may comprise a silicondioxide (SiO₂) or a silicon nitride (SiN). The interlayer dielectric isutilized to insulate adjacent metal lines (not shown) and reduceundesired capacitive coupling.

To interconnect the metal contact 302 with additional levels ofmetallization, a portion of the metal contact 302 needs to be exposedand a low resistance metal fill utilized to interconnect the differentinterconnection levels. In more detail, FIG. 3B illustratessemiconductor device structure 306 which comprises the metal contact 302and a remaining portion of the interlayer dielectric 304′. Thesemiconductor device structure 306 also includes a contact hole 308which may be formed by etching a portion of the interlayer dielectric304 until the underlying metal contact is exposed, thereby exposingmetallic surface 310.

The method of fabricating a semiconductor device structure according tothe embodiments of the disclosure may continue with reference to FIG.3C, wherein FIG. 3C illustrates semiconductor device structure 312 whichcomprises the metal contact 302, the remaining portion of the interlayerdielectric 304′, the contact hole 308 and selective metallic film 314.As illustrated in FIG. 3C, the selective metallic film 314, e.g., atungsten (W) film, is disposed directly above the remaining interlayerdielectric 304′ and not disposed above the metal contact 310.

The fabrication of the contact structure may be completely by fillingthe remaining portion of the contact hole with a low resistance contactplug, as illustrated by the semiconductor device structure 316 in FIG.3D. As illustrated in FIG. 3D, the remaining portion of the contact holeis filled with a low resistance contact plug 318, which is someembodiments may comprise a low resistance tungsten (W) contact plug. Insome embodiments of the disclosure, the low resistance contact plug 318may be deposited by the methods of the disclosure, or alternatively thelow resistance contact plug 318 may be deposited by chemical vapordeposition (CVD). The semiconductor device structure 316 may be furtherprocessed to form a planar surface 320, for example, the structure maybe subjected to one or more of a polishing or a chemical mechanicalpolishing of the upper surface of the semiconductor device structurethereby forming planar surface 320. The semiconductor device structure316 can be further processed to add additional metal connection levelscomprising one or more additional interlayer dielectric layers andmetallization layers.

The embodiments of the disclosure therefore include a semiconductordevice structure comprising a metallic film deposited by the methodsdisclosed herein. In some embodiments, the semiconductor devicestructure may comprise a tungsten film disposed directly over adielectric surface. In some embodiments, the semiconductor devicestructure may comprise a contact structure including an interlayerdielectric and a copper contact, wherein the copper contact is not indirect contact with a barrier metal, i.e., the surface of the coppercontact is free of a barrier metal, such as, for example, a titaniumnitride (TiN) barrier metal. In additional embodiments of thedisclosure, the contact metal, e.g., a copper contact, is not coveredwith a tungsten (W) nucleation layer, i.e., a high resistance tungsten(W) nucleation layer. Therefore, the embodiments of the disclosure maybe utilized to fabricate a contact structure consisting of a coppercontact, a selective tungsten film and a tungsten contact plug. In someembodiments, the contact structure formed by the embodiments of thedisclosure may have an electrical resistivity of less than 1000 Ohm·cm²,or less than 500 Ohm·cm², or less than 350 Ohm·cm², or less than 200Ohm·cm², or even less than 100 Ohm·cm².

The example embodiments of the disclosure described above do not limitthe scope of the invention, since these embodiments are merely examplesof the embodiments of the invention, which is defined by the appendedclaims and their legal equivalents. Any equivalent embodiments areintended to be within the scope of this invention. Indeed, variousmodifications of the disclosure, in addition to those shown anddescribed herein, such as alternative useful combination of the elementsdescribed, may become apparent to those skilled in the art from thedescription. Such modifications and embodiments are also intended tofall within the scope of the appended claims.

1. A method for selectively depositing a metallic film on a substratecomprising a first dielectric surface and a second metallic surface, themethod comprising; exposing the substrate to a passivating agent;performing a surface treatment on the second metallic surface; andselectively depositing the metallic film on the first dielectric surfacerelative to the second metallic surface wherein performing a surfacetreatment on the second metallic surface further comprises removing apassivating layer from the second metallic surface, and wherein removingthe passivating layer from the second metallic surface comprisesexposing the passivating layer to formic acid.
 2. (canceled)
 3. Themethod of claim 1, wherein exposing the substrate to a passivating agentand performing a surface treatment on the second metallic surface areperformed at a substrate temperature of greater than approximately 250°C.
 4. The method of claim 1, further comprising out-gassing thesubstrate prior to exposing the substrate to the passivating agent. 5.The method of claim 4, wherein out-gassing the substrate furthercomprises out-gassing the substrate at temperature greater thanapproximately 250° C. for a time period greater than approximately 15seconds.
 6. The method of claim 1, wherein the passivating agentcomprises an alkylhalosilane.
 7. The method of claim 1, wherein thepassivating agent comprises trimethyl(dimethylamino)silane.
 8. Themethod of claim 1, wherein exposing the substrate to a passivating agentfurther comprises exposing the substrate to a passivating agent for atime period of greater than 15 seconds.
 9. The method of claim 1,wherein the passivating layer comprises benzotriazole or a benzotriazolederivative.
 10. (canceled)
 11. The method of claim 1, wherein the secondmetallic surface comprises a copper oxide and exposing the passivatinglayer to formic acid reduces the copper oxide to copper.
 12. The methodof claim 1, wherein exposing the substrate to a passivating agent andperforming a surface treatment on the second metallic surface areperformed in a first reaction chamber and selectively depositing themetallic film is performed in a second reaction chamber.
 13. The methodof claim 1, wherein selectively depositing the metallic film comprisesperforming one or more sequential deposition cycles, each depositioncycle comprising alternating contacting the substrate with a metalcontaining precursor and a reducing agent precursor.
 14. The method ofclaim 1, wherein selectively depositing the metallic film furthercomprises heating the substrate to a temperature of greater thanapproximately 50° C.
 15. The method of claim 13, wherein the metalcontaining precursor comprises at least one of tungsten hexafluoride(WF₆), tantalum pentafluoride (TaF₅), niobium pentafluoride (NbF₅),titanium tetrafluoride (TiF₄), a molybdenum fluoride (MoF_(x)) or avanadium fluoride (VF_(x)).
 16. The method of claim 13, wherein thereducing agent precursor comprises at least one of hydrogen (H₂), ahydrogen (H₂) plasma, an ammonia (NH₃) plasma, ammonia (NH₃), silane(SiH₄), disilane (Si₂H₆), trisilane (Si₃H₈), germane (GeH₄), digermane(Ge₂H₆), or diborane (B₂H₆).
 17. The method of claim 1, wherein themetallic film comprises tungsten (W).
 18. The method of claim 1, whereinthe selectivity is greater than about 90%.
 19. A semiconductor devicestructure comprising the metallic film deposited by the method ofclaim
 1. 20. The semiconductor device structure of claim 19 wherein themetallic film comprises a tungsten film disposed over the firstdielectric surface.
 21. A method for selectively depositing a metallicfilm on a substrate comprising a first dielectric surface and a secondmetallic surface, the method comprising; exposing the substrate to apassivating agent; performing a surface treatment on the second metallicsurface; and selectively depositing the metallic film on the firstdielectric surface relative to the second metallic surface, whereinperforming a surface treatment on the second metallic surface furthercomprises removing a passivating layer, comprising benzotriazole or abenzotriazole derivative, from the second metallic surface.
 22. Themethod of claim 21, further comprising out-gassing the substrate priorto exposing the substrate to the passivating agent.